两种介质接触面剪切力学性能的试验研究

Experimental study on shear mechanical behaviors of interface between two kinds of media

采用直剪试验研究一体两介质和两体两介质接触界面力学性能的影响,以砂浆和混凝土构造宽度方向一致不同形状因子λ的不规则接触面,用以模拟工程体和地质体的相互作用。根据直剪试验,分析了一体两介质试件和两体两介质试件的破坏状态及应力–位移曲线,得到结论:界面黏结力和正应力对两介质接触面的力学性能有很大影响;形状因子λ在中低等法向力下对于两体两介质接触面的剪切力学性能有着重要的影响,在高法向应力下接触面的剪切力学性能则由弱介质的强度等因素决定;由于破坏的状态和受力的方式不同,在中低等法向力下,一体两介质的峰值抗剪强度大于两体两介质的峰值抗剪强度;在高法向应力下,恰恰相反。

Direct shear tests are carried out to investigate the influence of the interface on the mechanical behaviors of bi-material and the bi-body. A special specimen, casted with both mortar and concrete and formed irregular asperities in the interface between bi-material is employed to simulate the interaction of structural body and geo-body. According to the direct shear tests, the failure pattern and stress-displacement curves of bi-material specimens and bi-body specimens are analyzed. The main results are as follows： the cohesion effect and normal stress have a key influence on the mechanical behaviors of the interface; and under the middle- and low-grade normal stresses, the shape factor 2 has an important influence on the shear mechanical properties of the interface of bi-body. However, under the high normal stress, the shear mechanical properties of the interface are determined by the strength of attenuating medium. Because of the difference of the failure pattern force form, under the middle- and low-grade normal stresses, the peak shear strength of the bi-material specimens is larger than that of the bi-body specimens. However, under the high normal stress, the result is opposite.